Convert a String to a byte array and then back to the original String

Question

Is it possible to convert a string to byte array and then convert it back to the original string in Java or Android   My objective is to send some strings to a microcontroller  Arduino  and store it into EEPROM  which is only 1 nbsp KB   I tried to use an MD5 hash  but it seems it s only a one way encryption  What can I do to deal with this issue

User · Accepted Answer

I would suggest using the members of string, but with an explicit encoding:

byte[] bytes = text.getBytes("UTF-8");
String text = new String(bytes, "UTF-8");

By using an explicit encoding (and one which supports all of Unicode) you avoid the problems of just calling text.getBytes() etc:

You're explicitly using a specific encoding, so you know which encoding to use later, rather than relying on the platform default.
You know it will support all of Unicode (as opposed to, say, ISO-Latin-1).

EDIT: Even though UTF-8 is the default encoding on Android, I'd definitely be explicit about this. For example, this question only says "in Java or Android" - so it's entirely possible that the code will end up being used on other platforms.

Basically given that the normal Java platform can have different default encodings, I think it's best to be absolutely explicit. I've seen way too many people using the default encoding and losing data to take that risk.

EDIT: In my haste I forgot to mention that you don't have to use the encoding's name - you can use a Charset instead. Using Guava I'd really use:

byte[] bytes = text.getBytes(Charsets.UTF_8);
String text = new String(bytes, Charsets.UTF_8);

User · Answer

You can do it like this   String to byte array  String stringToConvert    This String is 76 characters long and will be converted to an array of bytes   byte   theByteArray   stringToConvert getBytes      http   www javadb com convert-string-to-byte-array  Byte array to String  byte   byteArray   new byte    87  79  87  46  46  46   String value   new String byteArray     http   www javadb com convert-byte-array-to-string

User · Answer

import java io FileInputStream  import java io ByteArrayOutputStream   public class FileHashStream           write a new method that will provide a new Byte array  and where this generally reads from an input stream  public static byte   read InputStream is  throws Exception       String path      type in the absolute path for the  commons-codec-1 10-bin zip              must need a Byte buffer      byte   buf   new byte 1024   16          we will use 16 kilobytes      int len   0          we need a new input stream      FileInputStream is   new FileInputStream path           use the buffer to update our  MessageDigest  instance      while true                len   is read buf           if len  lt  0  break          md update buf  0  len                 close the input stream      is close            call the  digest  method for obtaining the final hash-result      byte   ret   md digest         System out println  Length of Hash      ret length        for byte b   ret                System out println b                     String compare    49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d        String verification   Hex encodeHexString ret        System out println         System out println             System out println verification        System out println  Equals      verification equals compare

User · Answer

Use  String getBytes    1  to convert to bytes and use  String byte   data   2  constructor to convert back to string

[java] Convert a String to a byte array and then back to the original String

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